Given a power upgrade is in the future, there is some merit in maintaining a 3phase delta system. Harmonics, efficiency ground fault protection and other topics come to mind.
For those circuits that are in need of a 347 volt source and given there are times when the load is not balanced, an artificial neutral may be a consideration. The auto transformer connections provided by Bjarney appear to provide an artificial neutral but "tuning" may be a problem. Any change in load characteristics re: size or load sharing may be an issue. As well, the capital cost of the 1.5 kva xformers may be about the same cost as 22.5 kva delta/star dry core 1/1 ratio transformer.
I should ask what the rural voltage in Clyde's area is. Is there 600 volt 3P4W primary easily available or will the upgrade have to deal with a 3P3W in any event? Wiull the local utility provide a 4 wire system but at what cost?
I know in a lot of Rural Ontario 3P3W @600 volt is a local utility voltage -- 4160 on up to 35KV and a transformer allowance as part of bigger projects.
Just thinking out loud.....
Doug.....et al
